U.S. Provisional Application No. 61/128,483, filed May 22, 2008, is incorporated herein in its entirety by reference.
Current grain holding systems, such as combine grain tank unloading systems of combine harvesters, typically consist of single or multiple apparatus, typically, a cross conveyor or conveyors, that feed grain to an unloader conveyor or conveyors, typically a vertical unloader conveyor including an unloader conveyor element, such as an auger, operable for lifting the grain to a generally horizontal conveyor or auger that conveys the grain to a truck or other holding bin. Currently, most cross, vertical and horizontal conveyors or augers start and shut off simultaneously. This simultaneous action causes several issues, namely, one can only operate the system at a maximum unload or discharge rate, and, in situations in which the system is halted in the loaded condition, start up torques of a loaded conveyor can be excessive and result in failure.
As a result, it would be desirable to have a capability to control the maximum unload rate of an unloader conveyor, for instance, to more accurately meter grain to top off trucks or other receptacles, and to fill smaller wagons and receptacles. Likewise, it would be desirable to have a capability to shut off the horizontal cross conveyor or augers to stop the feed of grain to the vertical unloader conveyor or auger in advance of shutdown. This would allow the vertical unloader conveyor or auger to empty before shutdown. A reason for this is that the vertical unloader auger is typically more inefficient and takes longer to empty than a horizontal auger. Another reason would be to eliminate the subsequent gross start up torque and power requirements, which, as noted above, can reduce the working life of components due to early failure, and can require higher product cost. In this latter regard, the system must be designed to handle the initial peak start up torque, which will typically last for just two seconds or so, and is significantly greater than normal operating torque.
Additionally, after use, if the unloader conveyor is not cleaned out, remaining grain has been observed to have a tendency to settle in the enclosed lower region of the vertical unloader conveyor around the lower end of the auger therein and the adjacent end of the cross conveyor adjacent to the inlet opening. As a result, an additional problem that can occur if the cross conveyor and unloader conveyor are started simultaneously, or the cross conveyor is started first, is that the cross conveyor can force or pack the grain into and against the grain in the lower unloader conveyor housing, thereby causing grinding, cracking of, and other damage to the grain.
Reference Talbi et al., U.S. Pat. No. 7,452,180, which discloses a grain tank unloader and clean out control, which, when an unload command is received, will automatically initiate operation of the unloader conveyor, then, after a delay, automatically initiate operation of the grain tank or cross conveyor for feeding grain into the inlet end of the unloader conveyor, to overcome some of the start up problems. And, during operation, when a cleanout command is received, the control will automatically cease operation of the grain tank conveyor, then, after a sufficient time period for the unloader conveyor to empty, automatically cease operation of the unloader conveyor. These are desirable features, but an initial or start up delay is not always required, and in some instances, can be more advantageously shortened, or lengthened. Additionally, no provision is provided for controlling operation for topping off and the like.
What is sought therefore, is a manner of controlling feeding of grain to an unloader conveyor of a grain holding device, which overcomes one or more of the problems, and provides one or more of the features, set forth above.